Growth and Aflatoxin Production by Aspergillus parasiticus NRRL 2999 in the Presence of Acetic or Propionic Acid and at Different Initial pH Values

1987 ◽  
Vol 50 (11) ◽  
pp. 909-914 ◽  
Author(s):  
GULAM RUSUL ◽  
FATHY E. EL-GAZZAR ◽  
ELMER H. MARTH
Keyword(s):  
Acetic Acid ◽  
Propionic Acid ◽  
Aflatoxin B1 ◽  
Maximum Concentration ◽  
Aspergillus Parasiticus ◽  
Dry Weight ◽  
Aflatoxin Production ◽  
Lag Phase ◽  
Significant Difference ◽  
Initial Ph

Experiments were done to determine effects of different concentrations of acetic or propionic acid in a glucose-yeast extract-salts medium with an initial pH value of 4,5 or 5.5 on growth and aflatoxin production by Aspergillus parasiticus NRRL 2999. Amounts of aflatoxin were measured with reversed-phase high-performance liquid chromatography. The maximum concentration of acetic or propionic acid that permitted growth at an initial pH of 5.5 was 1% after 7 d of incubation and 0.25% after 3 d of incubation, respectively. When the initial pH of the medium was 4.5, the maximum concentration of acetic or propionic acid that permitted growth was 0.25 or 0.1%, respectively. There was no significant difference (p>0.05) in amount of mycelial (dry weight) produced by cultures in the presence of 0.0, 0.25, 0.50 or 0.75% acetic acid. Amounts of aflatoxin B1 and G1 produced decreased with an increasing concentration of acetic acid. Increasing concentrations of propionic acid caused a decrease in the amount of mycelial dry weight and aflatoxin produced by cultures growing in the medium with an initial pH of 5.5. At an initial pH of 4.5 mycelial growth was slow and at 3 d of incubation amounts of aflatoxin B1 and G1 produced were reduced as concentrations of acetic acid increased. This also was true for propionic acid in the medium with an initial pH of 4.5. Cultures with an extended lag phase in the presence of acetic or propionic acid overcame this and then produced large amounts of aflatoxin B1 and G1 at 7 and 10 d of incubation.

Growth and Aflatoxin Production by Aspergillus parasiticus NRRL 2999 in the Presence of Lactic Acid and at Different Initial pH values

1987 ◽  
Vol 50 (11) ◽  
pp. 940-944 ◽  
Author(s):  
FATHY E. EL-GAZZAR ◽  
GULAM RUSUL ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Aspergillus Parasiticus ◽  
Ph Value ◽  
Aflatoxin Production ◽  
Reversed Phase ◽  
Ph Values ◽  
Initial Ph ◽  
Medium Weight

Twenty-five milliliters of glucose-yeast-salts medium containing 0, 0.5, 0.75, 1.0, 1.5 and 2.0% lactic acid with an initial pH of 3.5 or 4.5 were inoculated with 1 ml of a spore suspension containing 106 conidia of Aspergillus parasiticus NRRL 2999 and incubated at 28°C for 10 d. The pH of the medium, weight of mycelium and aflatoxin production were determined after 3, 7, and 10 d of incubation. Amounts of aflatoxin produced were determined using reversed-phase high-performance liquid chromatography. Cultures grown in the presence of 0.5 and 0.75% lactic acid at an initial pH of 4.5 produced more aflatoxin B1 than did the other cultures at the end of 3 d of incubation. This was not true for aflatoxin G1; with increasing concentrations of lactic acid, cultures produced decreasing amounts of aflatoxin G1. Also, cultures growing in the medium with an initial pH of 3.5 produced more aflatoxin B1 in the presence of lactic acid at the end of 3 d of incubation than did control cultures. Cultures growing in the presence of 0.5 and 0.75% lactic acid produced the most aflatoxin. Maximum amounts of aflatoxin G1 were produced after 7 d of incubation, with cultures growing in the presence of 0.5 and 0.75% lactic acid producing the most. Lactic acid did not inhibit growth (mycelium weight) of cultures in the medium with initial pH values of 3.5 or 4.5 except there was a slight decrease in mycelial weight when the medium contained 0.5% lactic acid and had an initial pH value of 3.5.

Growth of and Aflatoxin Production by Aspergillus parasiticus in a Medium Containing Potassium Chloride or a Mixture of Potassium Chloride and Sodium Chloride

1986 ◽  
Vol 49 (11) ◽  
pp. 880-885 ◽  
Author(s):  
GULAM RUSUL ◽  
FATHY E. EL-GAZZAR ◽  
ELMER H. MARTH
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Sodium Chloride ◽  
Potassium Chloride ◽  
High Performance ◽  
Aspergillus Parasiticus ◽  
Dry Weight ◽  
Aflatoxin Production ◽  
Lag Phase ◽  
Reverse Phase

Twenty-five milliliters of glucose-yeast-salts medium containing 0, 2, 4, 6, 8 and 10% KCl or a mixture of NaCl (%) and KCl (%) (0:0, 1.5:0.5, 3.25:0.75, 4.75:1.25, 6.5:1.5, and 8:2) was inoculated with 1 ml of a spore suspension containing 106 conidia of Aspergillus parasiticus NRRL 2999 and incubated at 28°C for 10 d. The pH, dry weight of mycelium and aflatoxin production were determined after 3, 7 and 10 d of incubation. Amounts of aflatoxin produced were determined using reverse-phase high-performance liquid chromatography (HPLC). The mold growing in the presence of 0, 2 and 4% KCl produced maximum amounts of aflatoxin after 3 d, whereas in the presence of 6, 8 and 10% KCl it did so after 7 d. This trend was also true when the mold grew in the presence of mixtures of NaCl and KC1. Amounts of aflatoxin produced decreased with increasing concentrations of KCl or of the mixture of NaCl and KCl. The mycelial dry weight increased with increasing concentrations of KCl or the mixture of NaCl and KCl, although there was an extended lag phase at higher concentrations of both treatments.

Growth and Aflatoxin Production by Aspergillus parasiticus NRRL 2999 in the Presence of Potassium Benzoate or Potassium Sorbate and at Different Initial pH Values

1987 ◽  
Vol 50 (10) ◽  
pp. 820-825 ◽  
Author(s):  
GULAM RUSUL ◽  
ELMER H. MARTH
Keyword(s):  
High Performance ◽  
Aspergillus Parasiticus ◽  
Ph Value ◽  
Aflatoxin Production ◽  
Reversed Phase ◽  
Potassium Sorbate ◽  
Lag Phase ◽  
Ph Values ◽  
Initial Ph ◽  
Potassium Benzoate

Experiments were done to determine how different concentrations of potassium benzoate or potassium sorbate in a glucose-yeast extract-salts medium with an initial pH value of 3.5, 4.5 or 5.5 affected growth and aflatoxin production by Aspergillus parasiticus NRRL 2999. The pH of the medium, weight of mycelium and amount of aflatoxin produced were determined after 3 and 7 d of incubation. Aflatoxin was determined using reversed-phase high-performance liquid chromatography. Maximum concentrations of potassium sorbate and potassium benzoate that permitted growth were 0.2% and 0.4%, respectively, in a medium with an initial pH of 5.5. When the initial pH was 4.5, the maximum concentrations of potassium sorbate and potassium benzoate that permitted growth were 0.05% and 0.10%, respectively, but there was an extended lag phase. Increasing concentrations of potassium benzoate or potassium sorbate decreased amounts of aflatoxin B1 and G1 produced after 3 d in a medium with initial pH values of 5.5 or 4.5. Cultures growing in the medium containing 0.1, 0.15 or 0.20% potassium benzoate or potassium sorbate and with an initial pH of 5.5 were somewhat inhibited at 3 d of incubation, which was characterized by a slow decrease in pH, low mycelium dry weight and small amounts of accumulated aflatoxins. After 7 d these cultures overcame the initial inhibition and produced substantial amounts of aflatoxins and mycelium. This was also true for cultures growing in a medium with an initial pH of 4.5 and containing potassium benzoate or potassium sorbate. By decreasing the initial pH of the medium from 5.5 to 4.5, amounts of potassium benzoate or potassium sorbate required to achieve inhibition decreased by a factor of 10.

Sodium Benzoate in the Control of Growth and Aflatoxin Production by Aspergillus parasiticus

1987 ◽  
Vol 50 (4) ◽  
pp. 305-309 ◽  
Author(s):  
FATHY E. EL-GAZZAR ◽  
ELMER H. MARTH
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Aflatoxin B1 ◽  
Sodium Benzoate ◽  
High Performance ◽  
Aspergillus Parasiticus ◽  
Dry Weight ◽  
Aflatoxin Production ◽  
Reversed Phase ◽  
And Control

Sodium benzoate, 0.0, 0.1, 0.2, 0.3 or 0.4%, was added to a glucose-yeast-salts medium which was inoculated with 1 ml of a spore suspension containing 108 conidia of Aspergillus parasiticus NRRL 2999 and then was incubated at 28°C. Cultures were analyzed after 3, 7 and 10 d for mycelial dry weight, pH and accumulation of aflatoxin B1 and G1. Amounts of aflatoxin produced were determined using reversed-phase high performance liquid chromatography (HPLC). The percentage of inhibition or stimulation by the additive was used to make comparisons between treatments and control. Generally, increasing the concentration of sodium benzoate increased the percentage of inhibition at the end of incubation (10 d). However, the average accumulation of mycelial dry weight was greater in the presence of benzoate than in its absence, with the greatest increase occurring when the medium contained 0.3% sodium benzoate.

Aflatoxin Production in Black Currant, Blueberry and Strawberry Jams

1978 ◽  
Vol 41 (5) ◽  
pp. 344-347 ◽  
Author(s):  
O. PENSALA ◽  
A. NISKANEN ◽  
S. LINDROTH
Keyword(s):  
Yeast Extract ◽  
Raw Materials ◽  
Fungal Growth ◽  
Dry Weight ◽  
Aflatoxin Production ◽  
Fungal Mycelium ◽  
Black Currant ◽  
Initial Ph ◽  
Different Temperatures ◽  
Yeast Extract Sucrose

Unsweetened and sweetened (20 and 44% sucrose) black currant, blueberry and strawberry jams with spores of Aspergillus parasiticus NRRL 2999 were incubated at different temperatures and atmospheres for 0.5, 1, 2, and 6 months. Hyphal dry weight, pH of medium and aflatoxin production were examined. Also, the aflatoxin distribution between mold and jam layers was examined in jam with uncontrolled and controlled pH (initial pH 3.1–3.6 and 5.6 respectively) and in 20% yeast extract sucrose broth (initial pH 5.6) after 2 weeks of incubation. Aflatoxin was observed in black currant and strawberry jams stored at 22 and 30 C, but not in blueberry jam. Addition of sugar prevented production of aflatoxin in detectable amounts, although it enhanced fungal growth. Storage at 4 C resulted in a marked reduction in fungal growth. The high CO2 atmosphere prevented production of aflatoxin in detectable amounts in black currant and blueberry jams but not in strawberry jam. Raising the initial pH of the stored jam caused an increase in aflatoxin synthesis, although the amount of fungal mycelium, in contrast was reduced. Aflatoxin synthesis as a function of fungal growth was significantly weaker in the jams than in the yeast extract sucrose broth. The results imply that the jam raw materials, particularly blueberry, contain substances inhibiting production of atlatoxins. Alternatively, it is also possible that the jam materials contain only small amounts of nutrients necessary for synthesis of aflatoxin.

Effects of Potassium Sorbate on Growth and Aflatoxin Production by Aspergillus parasiticus and Aspergillus flavus1

1983 ◽  
Vol 46 (11) ◽  
pp. 940-942 ◽  
Author(s):  
LLOYD B. BULLERMAN
Keyword(s):  
Aspergillus Flavus ◽  
Yeast Extract ◽  
Aflatoxin B1 ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Potassium Sorbate ◽  
Mycelial Mass ◽  
Yeast Extract Sucrose

Growth and aflatoxin production by selected strains of Aspergillus parasiticus and Aspergillus flavus in the presence of potassium sorbate at 12°C were studied. Potassium sorbate at 0.05, 0.10 and 0.15% delayed or prevented spore germination and initiation of growth, and slowed growth of these organisms in yeast-extract sucrose broth at 12°C. Increasing concentrations of sorbate caused more variation in the amount of total mycelial growth and generally resulted in a decrease in total mycelial mass. Potassium sorbate also greatly reduced or prevented production of aflatoxin B1 by A. parasiticus and A. flavus for up to 70 d at 12°C. At 0.10 and 0.15% of sorbate, aflatoxin production was essentially eliminated. A 0.05% sorbate, aflatoxin production was greatly decreased in A. flavus over the control, but only slightly decreased in A. parasiticus.

scholarly journals Enhanced lipid production by Yarrowia lipolytica cultured with synthetic and waste-derived high-content volatile fatty acids under alkaline conditions

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruiling Gao ◽  
Zifu Li ◽  
Xiaoqin Zhou ◽  
Wenjun Bao ◽  
Shikun Cheng ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Yarrowia Lipolytica ◽  
Butyric Acid ◽  
Lipid Content ◽  
Volatile Fatty Acids ◽  
Lipid Production ◽  
Initial Ph ◽  
Alkaline Conditions

Abstract Background Volatile fatty acids (VFAs) can be effective and promising alternate carbon sources for microbial lipid production by a few oleaginous yeasts. However, the severe inhibitory effect of high-content (> 10 g/L) VFAs on these yeasts has impeded the production of high lipid yields and their large-scale application. Slightly acidic conditions have been commonly adopted because they have been considered favorable to oleaginous yeast cultivation. However, the acidic pH environment further aggravates this inhibition because VFAs appear largely in an undissociated form under this condition. Alkaline conditions likely alleviate the severe inhibition of high-content VFAs by significantly increasing the dissociation degree of VFAs. This hypothesis should be verified through a systematic research. Results The combined effects of high acetic acid concentrations and alkaline conditions on VFA utilization, cell growth, and lipid accumulation of Yarrowia lipolytica were systematically investigated through batch cultures of Y. lipolytica by using high concentrations (30–110 g/L) of acetic acid as a carbon source at an initial pH ranging from 6 to 10. An initial pH of 8 was determined as optimal. The highest biomass and lipid production (37.14 and 10.11 g/L) were obtained with 70 g/L acetic acid, whereas cultures with > 70 g/L acetic acid had decreased biomass and lipid yield due to excessive anion accumulation. Feasibilities on high-content propionic acid, butyric acid, and mixed VFAs were compared and evaluated. Results indicated that YX/S and YL/S of cultures on butyric acid (0.570, 0.144) were comparable with those on acetic acid (0.578, 0.160) under alkaline conditions. The performance on propionic acid was much inferior to that on other acids. Mixed VFAs were more beneficial to fast adaptation and lipid production than single types of VFA. Furthermore, cultures on food waste (FW) and fruit and vegetable waste (FVW) fermentate were carried out and lipid production was effectively improved under this alkaline condition. The highest biomass and lipid production on FW fermentate reached 14.65 g/L (YX/S: 0.414) and 3.20 g/L (YL/S: 0.091) with a lipid content of 21.86%, respectively. By comparison, the highest biomass and lipid production on FVW fermentate were 11.84 g/L (YX/S: 0.534) and 3.08 g/L (YL/S: 0.139), respectively, with a lipid content of 26.02%. Conclusions This study assumed and verified that alkaline conditions (optimal pH 8) could effectively alleviate the lethal effect of high-content VFA on Y. lipolytica and significantly improve biomass and lipid production. These results could provide a new cultivation strategy to achieve simple utilizations of high-content VFAs and increase lipid production. Feasibilities on FW and FVW-derived VFAs were evaluated, and meaningful information was provided for practical applications.

Growth and Aflatoxin Production by Aspergillus parasiticus in a Medium Containing Plant Hormones, Herbicides or Insecticides

1987 ◽  
Vol 50 (12) ◽  
pp. 1044-1047 ◽  
Author(s):  
R. S. FARAG ◽  
M. A. EL-LEITHY ◽  
A. E. BASYONY ◽  
Z. Y. DAW
Keyword(s):  
Acetic Acid ◽  
Gibberellic Acid ◽  
Plant Hormones ◽  
Aspergillus Parasiticus ◽  
Synthetic Medium ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Indol Acetic Acid ◽  
Acid Herbicides

The effect of some widely used plant hormones (indol-3-acetic acid and gibberellic acid), herbicides (gramoxone, stomp and treflan) and insecticides (malathion, actellic and guthion) on Aspergillus parasiticus growth and aflatoxin production in a synthetic medium was studied. Addition of indol acetic acid to the medium increased aflatoxin production more than gibberellic acid. Treflan at 5, 10 and 20 ppm levels caused a highly significant stimulatory effect on A. parasiticus growth and aflatoxin production. In contrast, stomp at 10 and 20 ppm produced the reverse effect. Guthion, an insecticide, caused a marked decrease in fungal growth and aflatoxin production. The inhibitory effect of insecticides under study on both fungal growth and aflatoxin production in effectiveness followed the sequence: guthion>actellic>malathion. At the recommended application rate (10 ppm), with the exception of indol acetic acid and treflan, all compounds suppressed mold growth and aflatoxin production.

Antifungal Activity of Chitosan and Its Preservative Effect on Low-Sugar Candied Kumquat

1994 ◽  
Vol 57 (2) ◽  
pp. 136-140 ◽  
Author(s):  
SHAO W. FANG ◽  
CHIN F. LI ◽  
DANIEL Y. C. SHIH
Keyword(s):  
Shelf Life ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Life Extension ◽  
Potassium Sorbate ◽  
Mold Growth ◽  
Chitosan Concentration ◽  
Significant Difference ◽  
Order Polynomial

The inhibitory effect of chitosan, a deacetylated form of chitin, on the growth of Aspergillus niger and the aflatoxin production of Aspergillus parasiticus was evaluated. The inhibitory effect of chitosan against A. niger was increased as the chitosan concentration was increased from 0.1 to 5.0 mg/ml (pH 5.4). At concentrations of 4.0 or 5.0 mg/ml, chitosan was less effective than potassium sorbate in inhibiting the growth of A. niger. The greatest inhibitory effect of chitosan against A. parasiticus was found at 3.0–5.0 mg/ml. In addition, chitosan could completely prevent aflatoxin production by A. parasiticus at the concentration of 4.0–5.0 mg/ml. Chitosan (2.0 and 5.0 mg/ml) induced considerable leakage of UV-absorbing and proteinaceous material of A. niger at pH 4.8. Using the response surface methodology, a second order polynomial model was derived and used to predict the number of days to obtain visible mold growth under various combinations of chitosan concentrations and °Brix in candied kumquat. The results showed that there was no significant difference in shelf-life extension of candied kumquat at chitosan concentration of 3.5–6.5 mg/ml. However, °Brix had a significant effect on shelf life. Candied kumquat with 6.0 mg/ml chitosan concentration and 61.9° Brix had a predicted mold-free shelf life of 65.3 d.

scholarly journals Antifungal and Antiaflatoxigenic Activities of 1,8-Cineole and t-Cinnamaldehyde on Aspergillus flavus

2018 ◽  
Vol 8 (9) ◽  
pp. 1655 ◽  
Author(s):  
Hyeong-Mi Kim ◽  
Hyunwoo Kwon ◽  
Kyeongsoon Kim ◽  
Sung-Eun Lee
Keyword(s):  
Propionic Acid ◽  
Aspergillus Flavus ◽  
Growth Medium ◽  
Aflatoxin B1 ◽  
Mode Of Action ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Inhibitory Effects ◽  
Aflatoxin B2

Aspergillus flavus and A. parsiticus produce aflatoxins that are highly toxic to mammals and birds. In this study, the inhibitory effects of 1,8-cineole and t-cinnamaldehyde were examined on the growth of Aspergillus flavus ATCC 22546 and aflatoxin production. 1,8-Cineole showed 50% inhibition of fungal growth at a concentration of 250 ppm, while t-cinnamaldehyde almost completely inhibited fungal growth at a concentration of 50 ppm. Furthermore, no fungal growth was observed when the growth medium was treated with 100 ppm t-cinnamaldehyde. 1,8-Cineole also exhibited 50% inhibition on the production of aflatoxin B1 and aflatoxin B2 at a concentration of 100 ppm, while the addition of 100 ppm t-cinnamaldehyde completely inhibited aflatoxin production. These antiaflatoxigenic activities were related to a dramatic downregulation of the expression of aflE and aflL by 1,8-cineole, but the mode of action for t-cinnamaldehyde was unclear. Collectively, our results suggest that both of the compounds are promising alternatives to the currently used disinfectant, propionic acid, for food and feedstuff preservation.

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